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INVESTIGATION OF THE IMPACT RESISTANCE OF AL3NI WHISKER REINFORCED ALUMINUM PREPARED BY UNIDIRECTIONAL SOLIDIFICATION.
UNITED AIRCRAFT RESEARCH LABS EAST HARTFORD CT
Al3Ni whisker reinforced aluminum was found to exhibit excellent toughness and little notch sensitivity even though its room temperature tensile elongation is only 2. This excellent toughness is maintained at liquid nitrogen temperature -196 C. It is postulated that this remarkable behavior is due to the presence of a continuous metal matrix which provides sufficient localized ductility in the vicinity of the crack tip to absorb considerable energy from the advancing crack. The impact behavior was found to be quite anisotropic. Of six orientations studied, the transverse orientation having the notch normal to the whisker axis was found to exhibit the lowest impact energy whereas the transverse orientation having the notch parallel to the whisker axis was found to exhibit the highest impact energy. A significant difference was noted between the impact behavior of material containing needle-like whiskers and that containing blade-like whiskers. Only two of the six orientations studied exhibited complete fracture for the material containing needle-like whiskers.
Final rept. 1 Jul 65-31 May 66,